I propose studies of membrane synthesis and differentiation, and of bacteriocin acton, in synchronously sporulating cultures of Bacillus megaterium. We will pulse label membrane proteins either during growth or during sporulation, and using techniques we have developed to separate membranes from different compartments of sporulating B. megaterium, we will determine whether proteins synthesized during a particular developmental stage are inserted into the membranes of a specific compartment. We will also seek differences in the protein complement of membranes from the forespore and sporangial compartments, using SDS- polyacrylamidde gel electrophoresis to separate membrane proteins and several techniques to label them. Radioactive, impermeant reagents which react only with membrane proteins exposed on the outside surface will be employed; iodination of exterior proteins with lactoperoxidase will be attempted, and the distribution of several specific proteins (membrane ATPase, megacin receptor) will be determined. The bacteriocin megacin FW337 will be characterized with respect to composition subunit structure, binding to sensitive cells, and mode of action. Using 125-I-labeled megacin, we will compare megacin binding and sensitivity during sporulation and germination, and we will compare binding to sensitive cells with that the megacin-resistant mutants. The effects of megacin upon membrane ATPase and transhydrogenase activities will be measured, and the possible relation between ATPase and megacin will be tested by immunological and biochemical techniques.